WTP menus targetIDs list ?https://www.eclipse.org/forums/index.php/mv/msg/72438/226518/#msg_226518
I had to find out a targetID to contribute to a context menu within XML
Schema editor. After searching for it in the docs without luck I finally
check it in the source code (it turned to be:
org.eclipse.wst.xsd.ui.popup.graph
org.eclipse.wst.xsd.core.xsdsource.source.EditorContext).

So I have a question, because I could not find any web page within
eclipse.org containing these two and as I can assume there are more like
these.
Is there any documentation/list of all used menu contribution
addresses/targetIDs?

No, that table isn't complete, but it does cover a lot of the common ids
that are used. Unforutnately the Ids are spread throughout the xml
files as well as in source code as many were programtically generated.